by Andrea Mandell, USA TODAY

by Andrea Mandell, USA TODAY

Buff and bronzed to rail-thin and (almost) back again. In Dallas Buyers Club (in theaters Friday), Matthew McConaughey shed almost 50 pounds to play AIDS patient Ron Woodroof, a bigoted Texas cowboy who turned his diagnosis into a business by selling antiviral drugs bought illegally in Mexico. Insiders say the film has all the ingredients for Oscar gold for the actor, who has undergone a stunning career overhaul at the box office.Here's a look at the 43-year-old star's complete transformation.

BEFORE:Last year, McConaughey launched an invigorated new chapter in his careerwith a series of lauded indies, including Bernie, Killer Joe, Mud and Magic Mike. Made for $7 million, Magic Mike's stripper tale grossed $167 million worldwide; Mud began its journey at Cannes and became distributor Roadside Attractions' biggest hit to date. After years of rom-coms and soft studio sells, McConaughey theorizes the right kind of projects came calling because he took a break and started saying no to the usual fare.Suddenly in Hollywood, "I became a 'good idea,'" he says, using air quotes. Four or five years ago, "maybe I wouldn't have been a 'good idea' for some of the things I've been doing (recently)."

DURING: In the months before Dallas Buyers Club was shot, financial backing fell through. Producers told the actor to quit his diet. "I just kept losing," says McConaughey, who ultimately lost almost 50 pounds. "I figured that was also a secret weapon to get it made. The train was kind of going on another level. " The film moved forward. Despite the weight loss, the actor says his energy level was up, and he needed only three hours of sleep a night. "My brain was on fire," he says.

AFTER:With Wolf of Wall Street, opening Christmas Day, and Christopher Nolan's Interstellar on the horizon, the actor has color back in his cheeks, and is currently sporting a much healthier frame. "I've gained 40 pounds back," he says. "Gaining it back was more fun but in a way more difficult. You have to be more careful." With the profoundly affective turn in Dallas Buyers Club, Oscar gold could be his. "I think he's a serious threat to win," says Oscarologist Tom O'Neil of GoldDerby.com. "It's a very courageous role."